The largest natural lake in Slovenia with many possibilities for activities. Bohinj Lake lies in the glacier-shaped lake bowl and has almost 100 million cubic meters of water.
After the old Bohemian joke only for one “cupboard”, if it is sufficiently large. The lake corridor, which rises steeply, is undistorted and without shallows. The flowing lake heats up to 22 ° C in summer, and in the winter it often freezes. The water of the water increases by 2 to 3 m in heavy rainfall.
Bohinj Lake information
- altitude: 526 m
- lake length: 4100 m (longest diagonal)
- maximum width: up to 1200 m
- water quantity: 92.5 million cubic meters
- maximum depth: 45 m
- lake surface: 318 ha
- length of the lake coast (not always the same measured): 11.35 km
Water in Bohinj Lake is renewed three times a year. The main stream is Savica, and the main outflow is Sava Bohinjka. More than a third of water flows through the Karst springs below the lake surface along the north coast. With a great rain, karst water is brought to the surface in the spring of Govic on the slopes of Pršivec).
Lake Bohinj History
at the end of the last ice age, Bohinj Lake was about 18 m higher (it reached the old Fužine)
only a tenth of Lake Bohinj is less than 10 m, 80% of which are deeper than 20 m, 20% are even 40 m
between the village of Sveti Duh and the event area Pod Skalco is the site of Lake Cretaceous
south of the Holy Spirit is one of the few sites of quartz porphyry in the Julian Alps
in Bohinj Lake there are as many as 65 species of algae, 8 species of molluscs and 5 species of fish
from Lake Bohinj, the second shortest river in Slovenia drains, Jezernica, named after Sava Bohinjka from the confluence with Mostnica (100 m from the bridge)
Lake Bohinj Activities
Lake Bohinj is suitable for water activities lovers in all seasons. In the warmer months, you can swim in it, ride with a boat, surf, kayak or canoe, catch fish and dive. Enjoy a wonderful panoramic boat trip with a tourist boat or just a relaxing walk along its coast.
In winter, sometimes (although less and more rarely), it also offers the possibility of skating (we warn you for caution and to skate at your own risk!).
is the largest permanent and natural lake in Slovenia , which lies in the Julian Alps in the northwest of the country. The main tributary of the lake is Savica , which in the western part of the lake basin penetrates through the sea with boulders and flows into the lake at Ukanc. The lake is flowing – from the lake flows the Jezernica River , which, after less than 100 m, along the left side , flows from the Vojnik to Mostnica , forms the river Sava Bohinjka . Near the northern edge of the lake there are several underwater karst springs, among which the best known is Govic .
It lies in the heart of the Triglav National Park and is considered to be the Slovenian natural landmark. In Slovenia, it exceeds only the intermittent Lake Cerknica (when filled) and the artificial lake of Ptuj .
Bohinj Lake Glacial tectonic origin
The lake basin is a glacial-tectonic origin, in its present form it was created about 10,000 years ago with the intense erosion action of the Bohinj Glacier , which was 800 meters thick at the last ice age maximum 20,000 years ago. The glacier bounced the bottom and covered it with the frontal seas in the eastern part of the lake. The Fužinarska planota and Pršivec in the north, Vogel in the south and the Komna plateau in the west rise steeply above the valley, while the lower Bohinj mountains are lower in the south-east .  
On the coast lie Ribcev Laz and Ukanc , while in the immediate vicinity there are also Stara Fužina , all belong to the Bohinj Municipality . Agriculture as a traditional economic activity has largely replaced tourism in the wider area of the lake . 
Lake Bohinj Hydrology
At the end of the last ice age, the lake’s glacier was 16 meters higher, at that time the lake reached the present-day Stara Fužina, which is reflected in the local fossil lake terraces. The western half is flooded by sediments brought by the Savica waterfall, which is, on average, 10 m thicker than the eastern one. At the deepest point of the lake, in the middle of the Fužine Bay in the east, the depth is 45 m. 80% of the lake is deeper than 20 m, 20% is deeper than 40 m. 
The karst area is not accurately delimited, and measures about 100 km². The Savica, which is the largest tributary, has an average flow of about 5 m³ / s, and the Jezernica outflow is 8.34 m³ / s. The difference is the underwater karst springs along the north coast. The lake is markedly flowing, it is estimated that the water in it is replaced three times a year.  The annual regime of fluctuations in the lake’s water level has the characteristics of the alpine snow-rain flow regime of rivers in the Julian Alps, with spring and autumn surpluses. The mean annual water level has been slightly lower since the beginning of the 20th century, and the autumn surplus is becoming more pronounced. 
The water is cold, the average monthly temperature of the surface varies from 1.6 ºC (February) to 18.1 ºC (August). The lowest measured temperature was 0 ºC and the highest temperature was 24.6 ºC (June 2003). In the summer there is a pronounced phenomenon of temperature stratification, presence of vertical temperature layers. At the top is a meter to a few meters deep epilimnium, where the water is heated by the sun and the temperature exceeds 20 ºC. Below it is a metallic (thermocline) with a pronounced gradient, where the temperature drops to at least 1ºC per meter of depth. In August this layer extends between 6 and 10 m depth. Below it is a hypolimny, where the temperature is constant 4 ºC. In the autumn, the top layers are cooled and the lake water completely mixed with the winds, so that the temperature stratification disappears. In winter, the bottom at 4 ºC is warmer than the water level, which can even freeze, and in the spring, the water again mixes completely due to rain and wind. 
According to the presence of nutrients, Bohinj Lake is still oligotrophic, which means that the nutrients are impaired.  Agriculture and tourism pose the greatest threat to this situation. 
Lake Bohinj Flora and fauna
Sailboats on the lake
There are 53 species of plankton algae known to the lake belonging to blue-green flares , dinoflagellates , diatoms , green and golden algae ; the species composition of phytoplankton varies with seasons.  Macrophytes of 18 species,  are limited to shallow areas of the bottom, in particular higher plants (for example, water ponds and hazelnuts ) found only in the shallows of some coves.  Among the zooplankton organisms, the most common water fleas ,copepod and kotačniki , they are characterized by a daily cycle of the vertical movement of the water column – day are kept at greater depths to avoid excessive sunlight and predators, evening move higher and kept on phytoplankton.  In addition to them, invertebrate fauna is developed, the so-called zoobenthos, which consists of about 60 species of organisms, mainly insect larvae , and less commonly there are snails , mussels , crustaceans , leeches , small bugs , swirls and wild worms . Varicose larvae are an indicator, that the water is still relatively pure.  There are also at least 16 species of fish , autochthonous, such as lake trout , tusk , sloth and bain , and 6 artificially inscribed. Of these, the lake is mostly problematic , which has almost completely supplanted the lake trout, and the bark that is extensively spreading. 
Lake Bohinj and Bohinjska Bistrica Sports and tourism
Although less well-known from nearby Lake Bled , Lake Bohinj with its surroundings is a popular place for active leisure time. In particular, hiking through the network of footpaths, climbing glacial boulders and landscaped climbing and paragliding at the expense of the warm air, which rises along the slopes above the lake, has been developed. The only lake offers opportunities for swimming, boating, sailing and diving. Local tourist societies have been organizing a triathlon steel show in the last few years , with swimming work on the lake. The use of motorboats in the lake is prohibited except for electrically powered vessels. 
The majority of settlements Ukanc and Ribcev Laz along the coast and the nearby Stara Fužina are made up of holiday homes, hotels and holiday homes. In Ukanc there is also a camping site, along the southern shore of the lake between Ukanc and Ribčev Laz, also the camp school Gozdna šola , the educational center of the Slovenian Association of Scouts . In the immediate vicinity of Ukanc is the lower station of the cable car to Vogel and the settlement is also the starting point for the ascent through Komarča and Komna.